JP6294406B2 - Compressor housing - Google Patents

Description

  The present invention relates to a compressor housing. More specifically, the present invention relates to a structure of a compressor housing including an impeller chamber and an intake duct.

  In a supercharging system for an internal combustion engine, a compressor provided in an intake passage of the internal combustion engine is rotationally driven by using exhaust energy or electric energy of the internal combustion engine, thereby pressurizing intake air supplied to the internal combustion engine. The compressor includes a compressor impeller, a compressor housing in which an impeller chamber that houses the compressor impeller, an intake duct that guides intake air to the impeller chamber, and the like are formed. Further, the internal combustion engine supercharging system includes an air flow meter for detecting the flow rate of intake air upstream of the compressor in the intake flow path, and the flow rate of intake air used for combustion in the internal combustion engine using the air flow meter. To control.

  By the way, when the air-fuel mixture or exhaust gas (hereinafter referred to as “blow-by gas”) that has flowed into the crankcase of the internal combustion engine is recirculated into the intake flow path via the breather flow path, the discharge thereof is suppressed. There are many. For example, as shown in Patent Document 1, in a supercharging system including a compressor as described above, blow-by gas may return to the downstream side of the air flow meter and the upstream side of the compressor impeller in the intake passage. Many.

JP 2005-226505 A

  FIG. 9 is a time chart showing a typical example of an operation pattern in which oil backflow described below can occur. FIG. 9 shows that the accelerator pedal is continuously depressed from time t0 and the load on the internal combustion engine is maximized, the accelerator pedal is released at time t1, the load on the internal combustion engine is minimized, and then the accelerator pedal is depressed at time t2. The case where the load of the internal combustion engine is maximized by depressing again is shown.

  FIG. 10 is a view showing the inside of a conventional compressor housing 100. More specifically, FIG. 10 shows the intake air of the compressor housing 100 immediately after the steady operation in which the load of the internal combustion engine is constant at the maximum under the operation pattern shown in FIG. 9, that is, immediately after time t1 in FIG. It is the figure which looked at the compressor impeller 102 provided in the duct 101 from the upstream of intake air.

  When a steady operation of the internal combustion engine is performed, the intake air in the intake duct 101 is scraped into the impeller chamber from the intake inlet 103 by the compressor impeller 102 that rotates clockwise in FIG. At this time, around the intake inlet 103 of the impeller chamber, a swirl flow in the same direction as the rotation direction of the compressor impeller 102 from the upstream side to the downstream side along the inner wall surface of the intake duct 101 as indicated by the broken arrow 104. Occurs. Most of the oil in the blow-by gas adhering to the inner wall surface of the intake duct 101 is sucked into the intake inlet 103 by this swirl flow, but a part of the oil is not sucked into the intake inlet 103 but around the intake inlet 103. May continue to turn. Therefore, when the accelerator pedal is turned off and the load on the internal combustion engine is reduced from the state of steady operation, the swirling flow around the intake air inlet 103 becomes weak, and the oil adhering to the inner wall surface becomes the bottom of the intake duct 101. In some cases, the oil reservoir 105 is formed as shown in FIG. 10 (corresponding to the period of time t1 to t2 in the time chart of FIG. 9).

  When the accelerator pedal is depressed again, the flow rate of the intake air from the intake duct 101 into the impeller chamber suddenly increases. At this time, surging occurs due to a sudden pressure change in the compressor housing 100, and the inside of the intake duct 101 is increased. In some cases, a strong swirling flow may occur from the compressor impeller 102 side toward the upstream side. Therefore, at the time of such re-acceleration, if the oil reservoir 105 exists in the intake duct 101 as shown in FIG. 10, the oil in the oil reservoir 105 is blown back from the intake duct 101 to the upstream side by a strong swirl flow, and the upstream side Oil may adhere to the air flow meter.

  An object of this invention is to provide the compressor housing which can suppress the blowback of the oil in blow-by gas to the intake upstream side.

  (1) A compressor housing (for example, a compressor housing 1 described later) is connected to a blow-by gas recirculation portion (for example, a blow-by gas inlet 83 described later) through which the blow-by gas of the internal combustion engine is recirculated in the intake passage of the internal combustion engine. Is also used for a compressor (for example, a later-described compressor 92C) that pressurizes intake air flowing through the intake passage using an impeller (for example, a later-described compressor impeller 5) provided on the downstream side. The compressor housing extends along an impeller chamber (for example, an impeller chamber 2 described later) that rotatably accommodates the impeller and an axis (for example, an axis C described later) of the impeller, and introduces intake air into the impeller chamber. An intake duct (for example, an intake duct 6 to be described later), and the intake duct is connected to an intake inlet (for example, an intake inlet 22 to be described later) formed in the impeller chamber. An inner wall surface 61) of the inner wall surface upstream of the intake inlet along the axis and in an arc shape along the circumferential direction of the impeller and from the axis in the radial direction of the impeller A stepped portion (for example, a stepped portion 67 to be described later) having a farther distance along the downstream side than the upstream side is formed.

  (2) In this case, the compressor housing preferably includes a breather duct (for example, a breather duct 8 to be described later) that extends along the radial direction of the impeller and introduces blow-by gas into the intake duct.

  (3) In this case, in the mounting posture of the compressor housing, a blow-by gas inlet (for example, a blow-by gas described later) connecting the inner peripheral surface (for example, an inner peripheral surface 82 described later) and the inner wall surface of the breather duct. The introduction port 83) is provided vertically above the intake introduction port, and a connection surface (for example, a connection surface 66 described later) connecting the blow-by gas introduction port and the intake introduction port in the inner wall surface is It is preferably substantially perpendicular to the axis.

  (4) In this case, a concave portion (for example, a concave portion 65 to be described later) is formed in a portion adjacent to the intake air inlet in a bottom portion (for example, a bottom portion 64 to be described later) that becomes the bottom in the mounting posture of the compressor housing in the inner wall surface. It is preferable that the step portion is formed on the upstream side of the concave portion along the axis.

  (5) In this case, it is preferable that the step portion is formed in a portion other than the bottom portion of the inner wall surface.

  (6) In this case, the stepped portion is located at a position higher than the lowest point (for example, the lowest point 221 described later) of the intake inlet at the side portion of the inner wall surface in the mounting posture of the compressor housing. It is preferable to extend along the circumferential direction to the blow-by gas inlet side.

  (7) The compressor housing adds the intake air flowing through the intake passage using an impeller provided downstream of the blow-by gas recirculation portion in which the blow-by gas of the internal combustion engine is recirculated among the intake flow passages of the internal combustion engine. Used for compressing compressors. The compressor housing includes an impeller chamber that rotatably accommodates the impeller, and an intake duct that extends along an axis of the impeller and introduces intake air into the impeller chamber, and the intake duct is formed in the impeller chamber An inner wall surface connected to the intake inlet port, the upstream side of the inner wall surface along the axis from the intake inlet port, the peripheral edge of the intake inlet port in the mounting posture of the compressor housing A groove (for example, a groove 68 described later) extending along the radial direction of the impeller from a position higher than the lowest point of the intake inlet is formed.

  (8) In this case, the compressor housing includes a reflux duct (for example, an EGR duct 7 or a breather duct 8 to be described later) that extends along the radial direction of the impeller and introduces blow-by gas or exhaust gas into the intake duct. Preferably, the groove extends from the periphery of the intake inlet to the inner peripheral surface side of the reflux duct.

  (9) In this case, in the mounting posture of the compressor housing, a reflux port (for example, an EGR inlet 73 described later) connecting the inner peripheral surface of the reflux duct and the inner wall surface is higher than the intake inlet. It is preferable that the groove is provided at a position and extends from the upper peripheral edge of the intake inlet (for example, a top 222 described later) toward the inner peripheral surface of the return duct.

  (1) In the compressor housing according to the present invention, an arc-shaped step portion along the circumferential direction of the impeller is formed on the upstream side of the inner wall surface of the intake duct along the axis of the impeller from the intake inlet. In addition, the stepped portion has a distance along the radial direction of the impeller from the axis that is farther downstream than the upstream side. In other words, this step portion becomes a wall for oil flowing along the inner wall surface from the downstream side to the upstream side of the intake air. Therefore, even if a strong swirling flow is generated in the intake duct from the downstream side to the upstream side in the state where the oil has accumulated in the vicinity of the intake inlet in the intake duct as described above, the flow of oil that travels on the inner wall surface On the other hand, since the step portion becomes a wall, it is possible to suppress the oil from being blown back to the upstream side beyond the step portion. This also prevents a sensor such as an air flow meter provided upstream from the intake duct from being contaminated by oil.

  (2) In the present invention, a breather duct extending along the radial direction of the impeller is provided in the compressor housing provided with the intake duct, and blow-by gas is recirculated into the intake duct from the breather duct. As described above, a swirling flow is generated in the intake duct. For this reason, in the conventional compressor housing, when the blow-by gas is recirculated into the intake duct of the compressor housing, the oil is likely to be accumulated in the intake duct, and the problem of the reflow of the oil to the upstream side of the intake becomes more prominent. On the other hand, in the present invention, since the oil is prevented from flowing out to the upstream side by the step formed in the intake duct, even if the blowby gas is recirculated into the intake duct of the compressor housing, The problem of rebirth is never revealed.

  (3) In the compressor housing of the present invention, the blow-by gas inlet is provided vertically above the intake inlet in the mounting posture, and further, the blow-by gas inlet and the intake inlet are connected on the inner wall surface of the intake duct. The connecting surface is substantially perpendicular to the axis. Thereby, the distance between the blow-by gas inlet and the intake inlet can be shortened as much as possible. The oil in the blow-by gas flowing from the blow-by gas introduction port travels along the connection surface and falls down to the intake introduction port by its own weight. If there is unevenness on the connection surface between the blow-by gas inlet and the intake inlet, the path is moved to the periphery of the intake inlet by the swirling flow while the oil drops vertically downward from the blow-by gas inlet. May end up. On the other hand, in the present invention, by making the connection surface substantially perpendicular to the axis, most of the oil in the blow-by gas can be poured into the intake air inlet, so the amount of oil accumulated in the intake duct can be reduced, As a result, oil blow-back can be further suppressed.

  (4) In the compressor housing according to the present invention, as described above, the stepped portion that becomes the wall with respect to the oil is provided along the axis rather than the concave portion formed in the bottom portion that becomes the bottom in the mounting posture among the inner wall surfaces of the intake duct. Form upstream. As described with reference to FIG. 10, the oil in the intake duct tends to accumulate in such a recess. Therefore, by providing the stepped portion on the upstream side of the recessed portion serving as the oil reservoir, even if the oil accumulated in the recessed portion flows upstream due to the strong reverse swirl flow as described above, the stepped portion further increases the upstream side. The outflow to can be suppressed.

  (5) In the compressor housing of the present invention, the step portion is formed in a portion other than the bottom portion of the inner wall surface. As described above, the stepped portion becomes a wall against the oil that flows backward from the downstream side to the upstream side. If such a stepped portion is formed at the bottom portion, there is a possibility that the amount of oil accumulated at the bottom portion increases. On the other hand, according to the present invention, by forming the stepped portion in a portion other than the bottom portion, it is possible to suppress the outflow to the upstream side without increasing the amount of oil accumulated in the intake duct.

  (6) In the compressor housing of the present invention, the step portion is on the blowby gas inlet side provided vertically above the intake inlet from a position higher than the lowest point of the intake inlet on the side of the inner wall surface in the mounting posture. It extends along the circumferential direction of the heimpeller. As a result, when the strong swirling flow as described above occurs in the oil collected in the vicinity of the lowest point of the intake inlet, the oil flows from the bottom side to the blow-by gas inlet side vertically above the stepped portion. In this way, the air flows into the intake inlet through a connecting surface formed substantially perpendicular to the axis. Therefore, according to the present invention, the oil accumulated at the bottom can be poured into the intake air inlet without being blown back to the upstream side.

  (7) In the compressor housing according to the present invention, the lowermost point of the intake inlet in the mounting posture among the peripheral edges of the intake inlet on the upstream side of the inner wall of the intake duct along the impeller axis from the intake inlet A groove extending along the radial direction of the impeller from a higher position is formed. As described with reference to FIG. 10, during the steady operation of the internal combustion engine, a swirling flow is generated in the intake duct from the upstream side to the downstream side. If the accelerator pedal is turned off, the oil may accumulate near the lowest point of the intake inlet. The groove of the present invention is substantially perpendicular to the direction of oil flow around the intake inlet during such steady operation. Therefore, the oil that swirls around the intake inlet on the inner wall surface of the intake duct along the circumferential direction of the impeller is changed in the direction of travel in this groove to the extending direction of the groove, that is, the radial direction of the impeller. The oil spreads along the groove. That is, according to the present invention, the oil swirling around the intake inlet during steady operation can be temporarily retracted in this groove, so that the lowest point of the intake inlet when the accelerator pedal is turned off. The amount of oil collected in the vicinity can be reduced. Therefore, according to the present invention, the amount of oil blown back from the upstream side to the downstream side when a strong swirling flow is generated in the intake duct from the downstream side toward the upstream side can be reduced. This also prevents a sensor such as an air flow meter provided on the upstream side of the intake duct from being contaminated with oil.

  (8) As described above, the groove portion of the present invention has a function of temporarily retracting oil, but a certain length is required to allow sufficient oil to be retracted. In the present invention, the compressor housing provided with the intake duct is provided with a reflux duct that extends along the radial direction of the impeller and introduces blow-by gas or exhaust into the intake duct, and the groove portion extends from the periphery of the intake inlet to the interior of the reflux duct. Extends to the circumferential side. That is, in the present invention, a sufficient amount of oil can be retreated into the groove portion by providing the groove portion using the space formed by providing the reflux duct.

  (9) In the compressor housing of the present invention, the groove portion extends from the upper peripheral edge of the intake inlet in the mounting posture to the inner peripheral surface side of the return duct. As a result, the oil temporarily retracted into the groove due to the swirling flow during steady operation as described above flows into the lower intake inlet through the groove when the accelerator pedal is turned off. The amount of oil collected in the vicinity of the lowest point can be reduced.

1 is a plan view of an engine room of a vehicle to which a compressor housing according to an embodiment of the present invention is applied. It is a front view of the compressor housing which concerns on the said embodiment. It is sectional drawing of the compressor housing which concerns on the said embodiment. It is sectional drawing of the compressor housing which concerns on the said embodiment. It is sectional drawing of the compressor housing which concerns on the said embodiment. It is a perspective view of the compressor housing which concerns on the said embodiment. It is sectional drawing of the compressor housing which concerns on the said embodiment. It is a perspective view of the compressor housing which concerns on the said embodiment. It is a time chart for demonstrating the subject of this invention. It is a figure which shows the mode of the inside of the conventional compressor housing.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view of an engine room ER of a vehicle equipped with a supercharging system S for an internal combustion engine (hereinafter referred to as “engine”). FIG. 1 shows devices that mainly constitute the intake system of the supercharging system S among various devices provided in the engine room ER. That is, FIG. 1 is a view of the supercharging system S in a state of being mounted in a predetermined mounting posture in the engine room ER as viewed from above in the vertical direction.

  The supercharging system S includes an air cleaner box 91 that purifies outside air, an exhaust turbine that converts exhaust energy into mechanical energy of a rotating shaft, and a compressor 92C that pressurizes intake air using a compressor impeller that will be described later connected to the rotating shaft. A turbocharger 92, an air intake pipe 93 that connects the air cleaner box 91 and the compressor 92C, an air flow meter 94 that detects the flow rate of the intake air flowing through the air intake pipe 93, an exhaust flow path of the compressor 92C and an engine (not shown) , And a breather pipe 96 that connects the compressor 92C and an engine crankshaft (not shown). FIG. 1 shows a state in which the exhaust turbine of the supercharger 92 is covered with a plate-like cover member 97.

  The intake pipe 93 extends substantially horizontally in its mounting posture, and connects the air cleaner box 91 and an after-mentioned intake duct formed in the compressor housing 1 constituting the main body of the compressor 92C. The main flow of the intake air purified by the air cleaner box 91 flows into the compressor housing 1 in the direction indicated by the arrow 98a in FIG. The air flow meter 94 is provided in a position closer to the air cleaner box 91 than the compressor housing 1 in the intake pipe 93.

  The EGR pipe 95 connects an exhaust passage (not shown) and an EGR duct (described later) formed in the compressor housing 1. Thereby, in the compressor housing 1, as shown by an arrow 98b in FIG. 1, a part of the engine exhaust (hereinafter also referred to as “EGR gas”) in a direction substantially perpendicular to the main flow of the intake air shown by the arrow 98a. Inflow.

  The breather pipe 96 connects a crankcase (not shown) and a later-described breather duct formed in the compressor housing 1. As a result, blow-by gas flows into the compressor housing 1 in a direction substantially perpendicular to the main flow of the intake air indicated by the arrow 98a, as indicated by the arrow 98c in FIG.

  In the supercharging system S, an EGR gas recirculation part (that is, an EGR duct 7 described later) in which EGR gas is recirculated and a blowby gas recirculation part (that is, a breather duct 8 described later) in which blowby gas is recirculated are provided in an air cleaner box. 91, the intake pipe 93 and the compressor housing 1 are provided on the downstream side of the air flow meter 94.

FIG. 2 is a front view of the compressor housing 1. More specifically, FIG. 2 is a view of the compressor housing 1 as viewed from the upstream side of the intake air along the axis of the compressor impeller that is rotatably accommodated in an impeller chamber 2 described later.
FIG. 3 is a cross-sectional view of the compressor housing 1. More specifically, FIG. 3 is a view of the cross section of the compressor housing 1 taken along the line IIa-IIa in FIG. 2 in the direction of the arrow A3. 2 and 3 are views of the compressor housing 1 in the mounting posture as viewed from the side. That is, the vertical direction in FIGS. 2 and 3 is equal to the vertical direction of the compressor housing 1 in the mounting posture.

  The compressor housing 1 is connected to an impeller chamber 2 that rotatably accommodates a compressor impeller 5 around a rotation axis R, a diffuser chamber 3, a scroll flow path 4, and an intake pipe 93 (see FIG. 1), so that intake air is taken in. An intake duct 6 to be introduced into the impeller chamber 2 and an EGR pipe 95 (see FIG. 1) are connected. An EGR duct 7 for introducing EGR gas into the intake duct 6 and a breather pipe 96 (see FIG. 1) are connected. A breather duct 8 for introducing a breather gas into the intake duct 6.

  The compressor impeller 5 includes a wheel 51 connected to a rotation shaft R that is driven to rotate by an exhaust turbine, and a plurality of blades 52 provided on a conical hub surface of the wheel 51. The blades 52 are provided at equal intervals along the circumferential direction on the hub surface of the wheel 51. Each blade 52 has a plate shape extending at a predetermined angular distribution from a front edge 53 that is an intake inlet toward a rear edge 54 that is an intake outlet. The tip end edge 55 of each blade 52 is formed along the surface shape of a shroud 21 (described later) that faces when the compressor impeller 5 is housed in the impeller chamber 2.

  In the impeller chamber 2, a shroud 21 that covers the side portion of the compressor impeller 5 is formed. The shroud 21 is a shroud surface having a shape along the tip end edge 55 from the front edge portion 53 to the rear edge portion 54 of the compressor impeller 5, more specifically, when the compressor impeller 5 rotates around the rotation axis R. A shroud surface having a shape substantially equal to the envelope surface formed by the tip end edge 55 is provided, and the tip end edge 55 which is a side portion of the compressor impeller 5 is covered by the shroud surface. The front edge 53 side of the shroud 21 is an intake inlet 22 having an inner diameter substantially equal to the outer diameter of the front edge 53. Further, the rear edge portion 54 side of the shroud 21 is an annular intake / discharge port having a width substantially equal to the height of the rear edge portion 54.

  When the turbine impeller of the exhaust turbine connected to the compressor impeller 5 by the rotation shaft R rotates by the energy of the exhaust, for example, when viewed from the upstream side of the intake air around the rotation shaft R (that is, in FIG. 2) Rotate clockwise. When the compressor impeller 5 rotates while being provided in the impeller chamber 2, it flows in along the axis C from the front edge 53 of each blade 52, flows between the blades 52, and has a diameter from each rear edge 54. It discharges toward the direction outside.

  The diffuser chamber 3 is annular and is formed so as to surround the intake / discharge port of the impeller chamber 2. In the diffuser chamber 3, linear blade rows are formed standing at predetermined intervals along the circumferential direction of the compressor impeller 5. As the compressor impeller 5 rotates, the intake air discharged radially outward from the rear edge 54 is decelerated in the process of flowing while expanding along the blade row formed in the diffuser chamber 3.

  The scroll passage 4 is annular and is formed so as to surround the diffuser chamber 3. The flow passage cross-sectional area of the scroll flow passage 4 gradually increases along the same direction as the rotation direction of the compressor impeller 5. The intake air discharged radially outward from the diffuser chamber 3 is further decelerated in the process of flowing through the scroll flow path 4, and then guided to the combustion chamber of the engine (not shown) via the intake exhaust duct 41 (see FIG. 2).

  The intake duct 6 has a substantially cylindrical shape extending along the axis C of the compressor impeller 5. The intake duct 6 includes an inner wall surface 61 connected to the intake inlet 22 formed in the impeller chamber 2. The intake air introduced by the intake pipe 93 of FIG. 1 is introduced into the impeller chamber 2 along the axis C through an intake passage formed by the inner wall surface 61 of the intake duct 6.

  As shown in FIGS. 2 and 3, the inner wall surface 61 of the intake duct 6 has a substantially cylindrical inner peripheral surface 62 having an inner diameter larger than the inner diameter of the intake inlet 22 of the impeller chamber 2 and extending along the axis C. And an annular shoulder surface 63 extending along the radial direction of the compressor impeller 5 and connecting the intake air inlet 22 having a smaller diameter than the inner peripheral surface 62. 2, the center 62C of the inner peripheral surface 62 when viewed along the axis C of the compressor impeller 5 in the mounting posture is slightly perpendicular to the center 22C of the intake inlet 22 of the impeller chamber 2. Eccentric upward. A specific configuration of the inner wall surface 61 will be described later in detail with reference to a cross-sectional view.

  The EGR duct 7 is a pipe member that communicates a pipe connection portion 71 provided outside the compressor housing 1 and an intake flow path formed by an inner wall surface 61 inside the intake duct 6. The above-described EGR pipe 95 (see FIG. 1) is connected to the pipe connection portion 71. Thereby, the EGR gas is recirculated into the intake duct 6. The inner peripheral surface 72 of the EGR duct 7 has a substantially cylindrical shape and extends along the radial direction of the compressor impeller 5. If the opening connecting the inner peripheral surface 72 of the EGR duct 7 and the inner wall surface 61 of the intake duct 6 is an EGR introduction port 73, the center of the EGR introduction port 73 is mounted on the compressor housing 1 as shown in FIG. In the posture, the air intake port 22 is provided at a position higher than the center 22C.

  The breather duct 8 is a pipe member that communicates a pipe connection portion 81 provided on the outside of the compressor housing 1 with an intake passage formed by an inner wall surface 61 inside the intake duct 6. The above-described breather pipe 96 (see FIG. 1) is connected to the pipe connection portion 81. Thereby, the blow-by gas is recirculated into the intake duct 6. The inner peripheral surface 82 of the breather duct 8 has a substantially cylindrical shape and extends along the radial direction of the compressor impeller 5. When the opening connecting the inner peripheral surface 82 of the breather duct 8 and the inner wall surface 61 of the intake duct 6 is a blow-by gas inlet 83, the blow-by gas inlet 83 is an intake inlet in the mounting posture of the compressor housing 1. 22 is provided above the vertical direction.

  FIG. 4 is a cross-sectional view of the compressor housing 1. More specifically, FIG. 4 is a view of the cross section of the compressor housing 1 taken along the line IIa-IIa in FIG. 2 in the direction of the arrow A4. A connection surface 66 connecting the intake inlet 22 and the blowby gas inlet 83 provided vertically above the shoulder surface 63 of the intake duct 6 is substantially perpendicular to the axis C as shown in FIG. In other words, the connection surface 66 that connects the blow-by gas inlet 83 and the intake air inlet 22 is not provided with irregularities that serve as a barrier for oil flowing along the wall surface. Thereby, the distance between the blow-by gas inlet 83 and the intake inlet 22 can be shortened as much as possible. This also allows most of the oil in the blow-by gas that is recirculated from the blow-by gas inlet 83 into the intake duct 6 to be drawn into the intake inlet 22 through the connection surface 66 by its own weight.

  Returning to FIG. 3, the portion of the inner peripheral surface 62 of the intake duct 6 adjacent to the intake inlet 22 in the bottom 64 that is the bottom in the mounting posture of the compressor housing 1 is lower than the lowest point 221 of the intake inlet 22. A recess 65 is formed. As described with reference to FIGS. 9 and 10, when the engine is normally operated, a swirling flow in the same direction as the rotation direction of the compressor impeller 5 is generated in the intake duct 6. Further, when such a swirl flow is generated, a part of the oil that drips down along the connection surface 66 (see FIG. 2 or 4) connecting the blow-by gas inlet 83 and the intake inlet 22 is taken into the intake inlet 22. In some cases, the air intake port 22 may continue to turn along the shoulder surface 63 without being sucked into the air. Thus, the oil swirling around the intake inlet 22 during steady operation of the engine accumulates in the recess 65 due to its own weight when the swirl flow becomes weak due to low load operation.

FIG. 5 is a cross-sectional view of the compressor housing 1. More specifically, FIG. 5 is a view of the cross section of the compressor housing 1 taken along the line III-III in FIG. 3 in the direction of the arrow A5.
FIG. 6 is a perspective view of the compressor housing 1. More specifically, FIG. 6 is a perspective view of the left side in FIG. 2 of the inner wall surface 61 of the compressor housing 1.

  As shown in FIGS. 3 and 5 to 6, an arc-shaped stepped portion 67 is formed along the circumferential direction of the compressor impeller 5 on the upstream side of the inner peripheral surface 62 along the axis C from the concave portion 65. ing. Further, the distance along the radial direction of the compressor impeller 5 from the axis C to the wall surface is farther downstream than the upstream with the stepped portion 67 as a boundary (see FIG. 5). Accordingly, the stepped portion 67 becomes a wall with respect to the flow of oil (see the arrow 5a in FIG. 5) that travels on the inner peripheral surface 62 from the recessed portion 65 provided on the downstream side to the upstream side. The position where the stepped portion 67 is formed is not limited to this. However, in order not to increase the amount of oil accumulated in the recess 65, the stepped portion 67 is preferably formed in a portion other than the bottom portion 64 of the inner peripheral surface 62.

  The stepped portion 67 is provided above the intake inlet 22 in the vertical direction from a position higher than the lowest point 221 of the intake inlet 22 on the side of the inner peripheral surface 62 of the intake duct 6 in the mounting posture of the compressor housing 1. It extends along the circumferential direction of the compressor impeller 5 toward the blow-by gas inlet 83 side.

  The effect of the stepped portion 67 will be described with reference to FIG. First, as described with reference to FIGS. 9 and 10, surging occurs when the accelerator pedal is depressed, and a strong swirling flow may occur in the intake duct 6 from the impeller chamber 2 side toward the upstream side. is there. At this time, if the oil is accumulated in the recess 65, the oil accumulated in the recess 65 by the strong reverse swirl flow flows along the inner peripheral surface 62 of the intake duct 6 to the upstream side. However, since the stepped portion 67 becomes a wall with respect to the flow of oil traveling along the wall surface, the oil blown back by the swirling flow in the reverse direction from the recess 65 extends the stepped portion 67 as shown by an arrow 6a in FIG. It runs up to the blow-by gas inlet 83 side in the direction, that is, the circumferential direction of the compressor impeller. The oil guided to the blow-by gas introduction port 83 side by the stepped portion 67 reaches a connection surface 66 that is substantially perpendicular to the axis C connecting the blow-by gas introduction port 83 and the intake air introduction port 22 (see FIG. 4). In FIG. 6, the air is sucked into the intake air inlet 22 through the connection surface 66 as indicated by an arrow 6 b. Thereby, according to the level | step-difference part 67, the blow-back to the upstream of the oil collected in the recessed part 65 is suppressed, and the suction | inhalation to the intake inlet 22 of the accumulated oil is accelerated | stimulated.

FIG. 7 is a cross-sectional view of the compressor housing 1. More specifically, FIG. 7 is a view of the cross section of the compressor housing 1 taken along the line IIb-IIb in FIG. 2 in the direction of the arrow A7.
FIG. 8 is a perspective view of the compressor housing 1. More specifically, FIG. 8 is a perspective view of a portion on the right side in FIG. 2 of the inner wall surface 61 of the compressor housing 1.

  As shown in FIGS. 2 and 7 to 8, the compressor impeller 5 extends from the peripheral portion of the intake inlet 22 to the upstream side of the shoulder surface 63 in the intake duct 6 along the axis C from the intake inlet 22. A substantially V-shaped groove 68 is formed in a cross-sectional view extending along the radial direction. The groove 68 extends along the radial direction of the compressor impeller 5 from the top 222 in the mounting posture of the compressor housing 1 in the peripheral edge of the intake air inlet 22 and is provided at a position higher than the intake air inlet 22 as described above. It reaches the EGR introduction port 73.

  The effect of the groove 68 will be described with reference to FIG. First, as described with reference to FIGS. 9 and 10, during the steady operation of the engine, a swirling flow is generated in the intake duct 6 from the upstream side to the impeller chamber 2 side. The oil in the blow-by gas continues to swirl around the intake inlet 22 along 63, and when the accelerator pedal is turned off, the oil may accumulate in the recess 65. The groove 68 extends along the radial direction of the compressor impeller 5, and the groove 68 is substantially perpendicular to the direction in which the oil flows during steady operation. Therefore, on the shoulder surface 63 on the inner side of the intake duct 6, the oil that swirls around the intake inlet 22 along the circumferential direction of the impeller as indicated by an arrow 8 a in FIG. It is changed in the extending direction of the groove 68, that is, the radial direction of the compressor impeller 5, and expands along both wall surfaces 68a and 68b constituting the groove 68 as shown by an arrow 8b in FIG. Therefore, according to this groove portion 68, the oil swirling around the intake inlet 22 during steady operation can be temporarily retracted without reaching the lower recess 65. Further, as described above, the base point of the groove 68 is the top 222 in the mounting posture of the peripheral edge of the intake inlet 22. Accordingly, the oil temporarily retracted into the groove 68 by the swirling flow during steady operation is provided below the groove 68 by its own weight as indicated by an arrow 8c in FIG. 8 when the accelerator pedal is subsequently turned off. Therefore, the amount of oil accumulated in the recess 65 can be reduced.

According to the compressor housing 1 of the present embodiment, the following effects can be obtained.
(1) In the compressor housing 1, an arc-shaped stepped portion 67 is formed along the circumferential direction of the compressor impeller 5 on the upstream side of the inner peripheral surface 62 of the intake duct 6 along the axis C from the intake inlet 22. To do. As a result, even if a strong swirling flow is generated in the intake duct 6 from the downstream side to the upstream side in a state where the oil is accumulated in the recess 65 near the intake inlet 22 in the intake duct 6, the inner peripheral surface 62. Since the stepped portion 67 becomes a wall with respect to the oil flow that travels through the oil, it is possible to suppress the oil from being blown back further upstream beyond the stepped portion 67. This also prevents the air flow meter 94 provided upstream from the intake duct 6 from being contaminated by oil.

  (2) In the compressor housing 1, a breather duct 8 extending along the radial direction of the compressor impeller 5 is provided, and blow-by gas is returned from the breather duct 8 into the intake duct 6. In the conventional compressor housing, when blow-by gas is recirculated into the intake duct of the compressor housing, oil easily accumulates in the intake duct, and the problem of reflow of oil to the upstream side of intake becomes more prominent. On the other hand, in the compressor housing 1, the stepped portion 67 formed in the intake duct 6 suppresses the outflow of oil to the upstream side. Therefore, even if the blowby gas is recirculated into the intake duct 6, as described above. The problem of oil blowback does not become apparent.

  (3) In the compressor housing 1, the blow-by gas introduction port 83 is provided vertically above the intake air introduction port 22 in the mounting posture, and further, the blow-by gas introduction port 83 and the intake air introduction port 22 in the shoulder surface 63 of the intake duct 6. The connection surface 66 connecting the two is substantially perpendicular to the axis C. As a result, most of the oil in the blow-by gas can be poured into the intake air inlet 22, so that the amount of oil that accumulates in the recess 65 in the intake duct 6 can be reduced, and the oil blow-back can be further suppressed.

  (4) In the compressor housing 1, the stepped portion 67 is formed on the upstream side along the axis C from the recessed portion 65 that is the bottom in the mounting posture on the inner peripheral surface 62 of the intake duct 6. As a result, even if the oil accumulated in the recess 65 flows to the upstream side due to the strong reverse swirl flow as described above, the stepped portion 67 can further suppress the outflow to the upstream side.

  (5) In the compressor housing 1, the stepped portion 67 is formed in a portion other than the bottom portion 64 of the inner peripheral surface 62. Thereby, the outflow to the upstream side can be suppressed without increasing the amount of oil accumulated in the recess 65 in the intake duct 6.

  (6) In the compressor housing 1, the stepped portion 67 is a blow-by provided vertically above the intake air inlet 22 from a position higher than the lowest point 221 of the intake air inlet 22 at the side portion in the mounting posture on the inner peripheral surface 62. It extends along the circumferential direction of the compressor impeller 5 toward the gas inlet 83. As a result, when a strong reverse swirling flow occurs, the oil accumulated in the recess 65 flows from the bottom 64 side along the stepped portion 67 to the blowby gas inlet 83 side vertically above, and is formed substantially perpendicular to the axis C. Then, the air flows into the intake air inlet 22 through the connected surface 66. As a result, the oil accumulated in the recess 65 can be poured into the intake air inlet 22 without being blown back to the upstream side.

  (7) In the compressor housing 1, on the upstream side of the shoulder surface 63 of the intake duct 6 along the axis C from the intake introduction port 22, the outermost periphery of the intake introduction port 22 in the mounting posture is the outermost periphery of the intake introduction port 22. A groove 68 extending along the radial direction from a position higher than the lower point 221 is formed. As a result, the oil swirling around the intake inlet 22 during steady operation can be temporarily retracted into the groove 68, so that the amount of oil that accumulates in the recess 65 when the accelerator pedal is turned off is reduced. Can do. As a result, the amount of oil blown back from the upstream side to the downstream side when a strong reverse swirling flow is generated in the intake duct 6 from the downstream side toward the upstream side can be reduced. This also prevents the air flow meter 94 provided on the upstream side of the intake duct 6 from being contaminated with oil.

  (8) In the compressor housing 1, an EGR duct 7 that extends along the radial direction of the compressor impeller 5 and introduces EGR gas into the intake duct 6 is provided, and the groove portion 68 extends from the periphery of the intake inlet 22 to the inner periphery of the EGR duct 7. It extends to the surface 72 side. That is, in the compressor housing 1, a sufficient amount of oil can be retreated in the groove 68 by providing the groove 68 using the space formed by providing the EGR duct 7.

  (9) In the compressor housing 1, the groove 68 extends from the top 222 at the periphery of the intake inlet 22 in the mounting posture toward the inner peripheral surface 72 of the EGR duct 7. As a result, the oil temporarily retracted into the groove 68 due to the swirling flow during steady operation flows through the groove 68 and into the lower intake inlet 22 when the accelerator pedal is turned off, so that the oil accumulated in the recess 65 The amount of can be reduced.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to this. Within the scope of the gist of the present invention, the detailed configuration may be changed as appropriate.

  In the above-described embodiment, the example in which the rotation direction of the compressor impeller 5 is clockwise when viewed from the upstream side has been described. However, the rotation direction of the compressor impeller 5 may be reversed.

  In the above-described embodiment, the case where the base point of the groove portion 68 is the top portion 222 in the mounting posture of the peripheral portion of the intake air inlet 22 has been described, but the present invention is not limited to this. As long as the base point of the groove 68 is higher than the lowest point 221 of the intake inlet 22 in the mounting posture, it may be any part of the peripheral edge of the intake inlet 22.

1. Compressor housing 2. Impeller chamber (impeller chamber)
22 ... Intake inlet 5 ... Compressor impeller (impeller)
6 ... Intake duct 61 ... Inner wall surface 61 (inner wall surface)
62 ... Inner peripheral surface (inner wall surface)
63 ... shoulder surface 63 (inner wall surface)
64 ... Bottom 65 ... Recess 66 ... Connection surface 67 ... Stepped portion 68 ... Groove 7 ... EGR duct (reflux duct)
73 ... EGR introduction port (reflux port)
8 ... Breather duct (breather duct, reflux duct)
82 ... Inner peripheral surface 83 ... Blow-by gas introduction port (blow-by gas recirculation part, blow-by gas introduction port, recirculation port)
92C ... Compressor R ... Rotary axis C ... Axis

Claims (9)

A compressor housing for a compressor that pressurizes intake air flowing through the intake passage using an impeller provided downstream of a blow-by gas recirculation portion in which the blow-by gas of the internal combustion engine is recirculated in the intake passage of the internal combustion engine. And
The compressor housing includes an impeller chamber that rotatably accommodates the impeller, and an intake duct that extends along an axis of the impeller and introduces intake air into the impeller chamber.
The intake duct includes an inner wall surface connected to an intake inlet formed in the impeller chamber,
On the upstream side of the inner wall surface along the axis from the intake inlet, the inner wall has an arc shape along the circumferential direction of the impeller, and a distance along the radial direction of the impeller from the axis is higher than the upstream side. A compressor housing characterized in that a stepped portion is formed farther on the downstream side.   The compressor housing according to claim 1, further comprising a breather duct that extends along a radial direction of the impeller and introduces blow-by gas into the intake duct. In the mounting posture of the compressor housing, a blow-by gas inlet that connects the inner peripheral surface of the breather duct and the inner wall surface is provided vertically above the intake inlet,
The compressor housing according to claim 2, wherein a connection surface connecting the blow-by gas inlet and the intake inlet of the inner wall surface is substantially perpendicular to the axis. A concave portion is formed in a portion of the inner wall surface adjacent to the intake inlet at a bottom portion which is a bottom in the mounting posture of the compressor housing,
4. The compressor housing according to claim 1, wherein the stepped portion is formed upstream of the concave portion along the axis. 5.   The compressor housing according to claim 4, wherein the step portion is formed in a portion other than the bottom portion of the inner wall surface.   The stepped portion extends along the circumferential direction from the position higher than the lowest point of the intake air inlet to the blowby gas inlet at a side portion of the inner wall surface in the mounting posture of the compressor housing. The compressor housing according to claim 3. A compressor housing for a compressor that pressurizes intake air flowing through the intake passage using an impeller provided downstream of a blow-by gas recirculation portion in which the blow-by gas of the internal combustion engine is recirculated in the intake passage of the internal combustion engine. And
The compressor housing includes an impeller chamber that rotatably accommodates the impeller, and an intake duct that extends along an axis of the impeller and introduces intake air into the impeller chamber.
The intake duct includes an inner wall surface connected to an intake inlet formed in the impeller chamber,
On the upstream side of the inner wall surface along the axis from the intake inlet, the peripheral edge of the intake inlet is positioned higher than the lowest point of the intake inlet in the mounting posture of the compressor housing. A compressor housing characterized in that a groove extending along the radial direction of the impeller is formed. The compressor housing includes a reflux duct that extends along a radial direction of the impeller and introduces blow-by gas or exhaust gas into the intake duct.
The compressor housing according to claim 7, wherein the groove portion extends from a peripheral edge of the intake air inlet to an inner peripheral surface side of the return duct.   In the mounting posture of the compressor housing, the return port connecting the inner peripheral surface of the return duct and the inner wall surface is provided at a position higher than the intake inlet, and the groove portion is an upper peripheral edge of the intake inlet. The compressor housing according to claim 8, wherein the compressor housing extends from an inner periphery of the return duct to an inner peripheral surface side.